replacing l.e.d liftgate brake light.

I have a 2002 Olds Bravada. The rear l.e.d. liftgage brakelight located
just above the rear glass is only half lit. Can this l.e.d. liftgate
brake light be changed via do-it yourself. The GM dealer wants $170 for
the part and another $150 to change.
Can this light be picked up as an aftermarket part? Any stores in
Canada anybody knows about?